In the course of downsizing supercharged combustion engines, the effect of the dynamic run-up delay of supercharger devices is intensified in a torque demand, the so-called turbo lag. One possible measure therefore consists of using electrically operable compressors instead of exhaust-gas-driven supercharger devices, or it consists of providing exhaust-gas-driven supercharger devices with electrical supplementary drives. Owing to the usually rapid response time of the electrically operable compressors, the build-up in charge pressure is able to take place significantly faster. The use of an electrically operable compressor allows for a power-oriented configuration of the supercharging operation, so that a clear increase in the specific power is able to be achieved.
The electrically operable compressor may be integrated into the charge-air path downstream from the intercooler, so that the volume to be compressed is as low as possible downstream from the electrically operable compressor.
In the case of exhaust-gas-driven supercharger devices featuring integrated electrical supplementation, referred to as cross chargers, the electrically operable compressor may be realized by an electrical supplementary drive provided at the mechanical coupling between an exhaust-gas turbine and the compressor, so that, in addition or as an alternative to the exhaust-gas enthalpy converted into mechanical energy, electrical energy can also be provided for driving the compressor.